merge mm-hotfixes-stable into mm-stable to pick up depended-upon changes

lib/maple_tree.c

@@ -4107,6 +4107,10 @@ static inline unsigned char mas_wr_new_end(struct ma_wr_state *wr_mas)
  * mas_wr_append: Attempt to append
  * @wr_mas: the maple write state
  *
+ * This is currently unsafe in rcu mode since the end of the node may be cached
+ * by readers while the node contents may be updated which could result in
+ * inaccurate information.
+ *
  * Return: True if appended, false otherwise
  */
 static inline bool mas_wr_append(struct ma_wr_state *wr_mas,
@@ -4116,6 +4120,9 @@ static inline bool mas_wr_append(struct ma_wr_state *wr_mas,
  struct ma_state *mas = wr_mas->mas;
  unsigned char node_pivots = mt_pivots[wr_mas->type];
 
+ if (mt_in_rcu(mas->tree))
+ return false;
+
  if (mas->offset != wr_mas->node_end)
  return false;
 

mm/huge_memory.c

@@ -1607,7 +1607,7 @@ bool madvise_free_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
  * If other processes are mapping this folio, we couldn't discard
  * the folio unless they all do MADV_FREE so let's skip the folio.
  */
- if (folio_mapcount(folio) != 1)
+ if (folio_estimated_sharers(folio) != 1)
  goto out;
 
  if (!folio_trylock(folio))

mm/madvise.c

@@ -383,7 +383,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
  folio = pfn_folio(pmd_pfn(orig_pmd));
 
  /* Do not interfere with other mappings of this folio */
- if (folio_mapcount(folio) != 1)
+ if (folio_estimated_sharers(folio) != 1)
  goto huge_unlock;
 
  if (pageout_anon_only_filter && !folio_test_anon(folio))
@@ -459,7 +459,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
  if (folio_test_large(folio)) {
  int err;
 
- if (folio_mapcount(folio) != 1)
+ if (folio_estimated_sharers(folio) != 1)
  break;
  if (pageout_anon_only_filter && !folio_test_anon(folio))
  break;
@@ -683,7 +683,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
  if (folio_test_large(folio)) {
  int err;
 
- if (folio_mapcount(folio) != 1)
+ if (folio_estimated_sharers(folio) != 1)
  break;
  if (!folio_trylock(folio))
  break;

mm/shmem.c

@@ -806,14 +806,16 @@ unsigned long shmem_partial_swap_usage(struct address_space *mapping,
  XA_STATE(xas, &mapping->i_pages, start);
  struct page *page;
  unsigned long swapped = 0;
+ unsigned long max = end - 1;
 
  rcu_read_lock();
- xas_for_each(&xas, page, end - 1) {
+ xas_for_each(&xas, page, max) {
  if (xas_retry(&xas, page))
  continue;
  if (xa_is_value(page))
  swapped++;
-
+ if (xas.xa_index == max)
+ break;
  if (need_resched()) {
  xas_pause(&xas);
  cond_resched_rcu();

tools/testing/selftests/cachestat/test_cachestat.c

@@ -4,17 +4,21 @@
 #include <stdio.h>
 #include <stdbool.h>
 #include <linux/kernel.h>
+#include <linux/magic.h>
 #include <linux/mman.h>
 #include <sys/mman.h>
 #include <sys/shm.h>
 #include <sys/syscall.h>
+#include <sys/vfs.h>
 #include <unistd.h>
 #include <string.h>
 #include <fcntl.h>
 #include <errno.h>
 
 #include "../kselftest.h"
 
+#define NR_TESTS 9
+
 static const char * const dev_files[] = {
  "/dev/zero", "/dev/null", "/dev/urandom",
  "/proc/version", "/proc"
@@ -90,20 +94,34 @@ bool write_exactly(int fd, size_t filesize)
  return ret;
 }
 
+/*
+ * fsync() is implemented via noop_fsync() on tmpfs. This makes the fsync()
+ * test fail below, so we need to check for test file living on a tmpfs.
+ */
+static bool is_on_tmpfs(int fd)
+{
+ struct statfs statfs_buf;
+
+ if (fstatfs(fd, &statfs_buf))
+ return false;
+
+ return statfs_buf.f_type == TMPFS_MAGIC;
+}
+
 /*
  * Open/create the file at filename, (optionally) write random data to it
  * (exactly num_pages), then test the cachestat syscall on this file.
  *
  * If test_fsync == true, fsync the file, then check the number of dirty
  * pages.
  */
-bool test_cachestat(const char *filename, bool write_random, bool create,
- bool test_fsync, unsigned long num_pages, int open_flags,
- mode_t open_mode)
+static int test_cachestat(const char *filename, bool write_random, bool create,
+  bool test_fsync, unsigned long num_pages,
+  int open_flags, mode_t open_mode)
 {
  size_t PS = sysconf(_SC_PAGESIZE);
  int filesize = num_pages * PS;
- bool ret = true;
+ int ret = KSFT_PASS;
  long syscall_ret;
  struct cachestat cs;
  struct cachestat_range cs_range = { 0, filesize };
@@ -112,7 +130,7 @@ bool test_cachestat(const char *filename, bool write_random, bool create,
 
  if (fd == -1) {
  ksft_print_msg("Unable to create/open file.\n");
- ret = false;
+ ret = KSFT_FAIL;
  goto out;
  } else {
  ksft_print_msg("Create/open %s\n", filename);
@@ -121,7 +139,7 @@ bool test_cachestat(const char *filename, bool write_random, bool create,
  if (write_random) {
  if (!write_exactly(fd, filesize)) {
  ksft_print_msg("Unable to access urandom.\n");
- ret = false;
+ ret = KSFT_FAIL;
  goto out1;
  }
  }
@@ -132,7 +150,7 @@ bool test_cachestat(const char *filename, bool write_random, bool create,
 
  if (syscall_ret) {
  ksft_print_msg("Cachestat returned non-zero.\n");
- ret = false;
+ ret = KSFT_FAIL;
  goto out1;
 
  } else {
@@ -142,15 +160,17 @@ bool test_cachestat(const char *filename, bool write_random, bool create,
  if (cs.nr_cache + cs.nr_evicted != num_pages) {
  ksft_print_msg(
  "Total number of cached and evicted pages is off.\n");
- ret = false;
+ ret = KSFT_FAIL;
  }
  }
  }
 
  if (test_fsync) {
- if (fsync(fd)) {
+ if (is_on_tmpfs(fd)) {
+ ret = KSFT_SKIP;
+ } else if (fsync(fd)) {
  ksft_print_msg("fsync fails.\n");
- ret = false;
+ ret = KSFT_FAIL;
  } else {
  syscall_ret = syscall(cachestat_nr, fd, &cs_range, &cs, 0);
 
@@ -161,13 +181,13 @@ bool test_cachestat(const char *filename, bool write_random, bool create,
  print_cachestat(&cs);
 
  if (cs.nr_dirty) {
- ret = false;
+ ret = KSFT_FAIL;
  ksft_print_msg(
  "Number of dirty should be zero after fsync.\n");
  }
  } else {
  ksft_print_msg("Cachestat (after fsync) returned non-zero.\n");
- ret = false;
+ ret = KSFT_FAIL;
  goto out1;
  }
  }
@@ -236,13 +256,29 @@ bool test_cachestat_shmem(void)
 
 int main(void)
 {
- int ret = 0;
+ int ret;
+
+ ksft_print_header();
+
+ ret = syscall(__NR_cachestat, -1, NULL, NULL, 0);
+ if (ret == -1 && errno == ENOSYS)
+ ksft_exit_skip("cachestat syscall not available\n");
+
+ ksft_set_plan(NR_TESTS);
+
+ if (ret == -1 && errno == EBADF) {
+ ksft_test_result_pass("bad file descriptor recognized\n");
+ ret = 0;
+ } else {
+ ksft_test_result_fail("bad file descriptor ignored\n");
+ ret = 1;
+ }
 
  for (int i = 0; i < 5; i++) {
  const char *dev_filename = dev_files[i];
 
  if (test_cachestat(dev_filename, false, false, false,
- 4, O_RDONLY, 0400))
+ 4, O_RDONLY, 0400) == KSFT_PASS)
  ksft_test_result_pass("cachestat works with %s\n", dev_filename);
  else {
  ksft_test_result_fail("cachestat fails with %s\n", dev_filename);
@@ -251,13 +287,27 @@ int main(void)
  }
 
  if (test_cachestat("tmpfilecachestat", true, true,
- true, 4, O_CREAT | O_RDWR, 0400 | 0600))
+ false, 4, O_CREAT | O_RDWR, 0600) == KSFT_PASS)
  ksft_test_result_pass("cachestat works with a normal file\n");
  else {
  ksft_test_result_fail("cachestat fails with normal file\n");
  ret = 1;
  }
 
+ switch (test_cachestat("tmpfilecachestat", true, true,
+ true, 4, O_CREAT | O_RDWR, 0600)) {
+ case KSFT_FAIL:
+ ksft_test_result_fail("cachestat fsync fails with normal file\n");
+ ret = KSFT_FAIL;
+ break;
+ case KSFT_PASS:
+ ksft_test_result_pass("cachestat fsync works with a normal file\n");
+ break;
+ case KSFT_SKIP:
+ ksft_test_result_skip("tmpfilecachestat is on tmpfs\n");
+ break;
+ }
+
  if (test_cachestat_shmem())
  ksft_test_result_pass("cachestat works with a shmem file\n");
  else {